This project is concerned primarily with the physiology and biochemistry of vertebrate retinal neurons, the processing of visual information within the retina, and the mechanisms underlying retinal responses. Both biochemical and physiological responses of retinal neurons to various neuroactive substances will be determined and analyzed for their significance in visual function. Specific problems to studied over the next grant period include: 1) Role of cyclic nucleotides in retinal neuronal function. 2) Effects of dopamine, cyclic AMP and other substances on the biochemistry and physiology of retinal neurons. 3) Effects of dopamine, aspartate, glutamate and other putative transmitter substances, including selected peptides, on the physiology of neurons in the intact, perfused retina.